Shi Yunbo, Miao Wang, Teng Junfang, Zhang Lingli
Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China.
Cell Physiol Biochem. 2018;45(1):212-225. doi: 10.1159/000486768. Epub 2018 Jan 22.
BACKGROUND/AIMS: Ginsenoside Rb1 (Rb1) has been reported to have varieties of neuroprotective effects. This study aimed to evaluate the effects of Rb1 on pentylenetetrazol (PTZ)-induced rat brain injury and Mg2+ free-induced neuron injury and analyzed the detailed molecular mechanisms in vivo and in vitro.
Seizure duration and latency were measured in epilepsy kindled rat. The cognitive impairment was assessed by Morris water maze (MWM) test. Oxidative stress parameters, malondialdehyde (MDA) and glutathione (GSH) were measured by the 2-thiobarbituric acid methods and the DTNB-GSSG reductase recycling methods. Neuronal damage was assessed by hematoxylin and eosin (H&E) and Nissl staining. Neuronal apoptosis was measured by Annexin V-FITC and propidium iodide (PI) staining. Immunohistochemistry and immunofluorescence staining were performed to evaluate Nrf2 and HO-1 expressions. Expression of Nrf2, HO-1, Bcl-2, iNOS and LC3 were evaluated by western blot.
The PTZ-injured rats presented longer seizure duration and shorter seizure latency. Rb1 ameliorated these effects, as well as the cognitive deficits caused by PTZ exposure. Besides, Rb1 dose-dependently increased GSH levels, decreased MDA levels and alleviated neuronal damage in PTZ-treated rats. In vitro, Rb1 increased cell viability and decreased neuronal apoptosis in a dose-dependent manner under Mg2+ free condition. Moreover, in vivo and in vitro, Rb1 enhanced both the Nrf2 and HO-1 expressions. Furthermore, upregulation of the expression of Bcl-2 and downregulation of the expression of iNOS and LC3 were observed. However, knockdown of Nrf2 adversely affected the protective effects of Rb1 in epileptic hippocampal neurons.
Rb1 conferred neuroprotective effects against PTZ-induced brain damage and Mg2+ free-induced neuron injury by activating Nrf2/ARE signaling.
背景/目的：据报道人参皂苷Rb1（Rb1）具有多种神经保护作用。本研究旨在评估Rb1对戊四氮（PTZ）诱导的大鼠脑损伤和无镁诱导的神经元损伤的影响，并分析体内和体外的详细分子机制。
在癫痫点燃大鼠中测量癫痫发作持续时间和潜伏期。通过莫里斯水迷宫（MWM）试验评估认知障碍。采用2-硫代巴比妥酸法和DTNB-GSSG还原酶循环法测量氧化应激参数丙二醛（MDA）和谷胱甘肽（GSH）。通过苏木精和伊红（H&E）染色及尼氏染色评估神经元损伤。采用膜联蛋白V-异硫氰酸荧光素（Annexin V-FITC）和碘化丙啶（PI）染色测量神经元凋亡。进行免疫组织化学和免疫荧光染色以评估核因子E2相关因子2（Nrf2）和血红素加氧酶-1（HO-1）的表达。通过蛋白质免疫印迹法评估Nrf2、HO-1、Bcl-2、诱导型一氧化氮合酶（iNOS）和微管相关蛋白1轻链3（LC3）的表达。
PTZ损伤的大鼠癫痫发作持续时间更长，癫痫发作潜伏期更短。Rb1改善了这些影响以及PTZ暴露引起的认知缺陷。此外，Rb1剂量依赖性地增加PTZ处理大鼠的GSH水平，降低MDA水平并减轻神经元损伤。在体外，在无镁条件下，Rb1以剂量依赖性方式增加细胞活力并减少神经元凋亡。此外，在体内和体外，Rb1均增强了Nrf2和HO-1的表达。此外，观察到Bcl-2表达上调以及iNOS和LC3表达下调。然而，敲低Nrf2会对Rb1在癫痫海马神经元中的保护作用产生不利影响。
Rb1通过激活Nrf2/抗氧化反应元件（ARE）信号通路对PTZ诱导的脑损伤和无镁诱导的神经元损伤具有神经保护作用。
